Concept and methodology for Scope 4 carbon accounting

Assessing carbon-negative and carbon-neutral strategies is critical for mitigating and adapting to global climate change. However, significant contributions to the carbon neutrality target from global green energy generation have not been adequately represented by current carbon accounting principles that focus mainly on direct carbon emissions from fossil fuel combustion (Scope 1), emissions from imported electricity (Scope 2), and supply chain emissions (Scope 3). We propose a new framework to account for “avoided carbon emissions” or Scope 4 emissions by defining them as the avoided emissions resulting from the use of noncarbon energy or the combustion of carbon-negative products instead of fossil fuels. This framework reflects the contributions of the development of carbon-neutral energy systems and carbon-negative technologies to global climate mitigation.